I have the following function in Lua:
function iffunc(k,str,str1)
if k ~= 0 then
return str .. k .. (str1 or "")
end
end
This function allows me to check if value k is populated or not. I'm actually using it to determine if I want to display something that has zero value. My problem is this: I'm trying to concatenate a string of iffunc(), but since some of the values are 0, it returns an error of trying to concatenate a nil value. For instance:
levellbon = iffunc(levellrep["BonusStr"],"#wStr#r{#x111","#r}") .. iffunc(levellrep["BonusInt"],"#wInt#r{#x111","#r}") .. iffunc(levellrep["BonusWis"],"#wWis#r{#x111","#r}")
If any of the table values are 0, it'll return the error. I could easily put 'return 0' in the iffunc itself; however, I don't want a string of 000, either. So how can I work it where no matter which values are nil, I won't get that error? Ultimately, I'm going to do an iffunc on the levellbon variable to see if that's populated or not, but I've got that part figured out. I just need to get past this little hurdle right now. Thanks!
I'd do this:
function iffunc(k,str,str1)
if k == 0 then return "" end
return str .. k .. (str1 or "")
end
You should add an else statement in the function, where you return an empty string ("").
Related
Hello guys i please need your help.
I have values, most of them are numbers but some of them are strings.
How can i check if value is string or number?
I already tried this code but when it reach string value i get error " attempt to perform arithmetic on local 'numberValue' (a nil value)"
function Config:IsNumber(value)
if value ~=nill or value ~=nil then
local numberValue = tonumber(value)
if numberValue/numberValue ==1 then
return true
else
return false
end
end
end
end
end
First of all let's start with errors in your code.
You have 2 ends to many.
it is nil, not nill. I'm not sure where you're going with that check.
Other issues / things to improve:
numberValue / numberValue == 1 does not make any sense. A number dividided by itself always results in 1. So checking that is pointless.
Also instead of
if something == 1 then
return true
else
return false
end
Can simply be replaced by return something == 1. There is no need for a conditional statement here.
To your question:
To check wether a value is a string use type(value) == "string".
To check wether a value can be convertet do a number use tonumber(value). It will either return a number or nil.
So according to your error the conversion to a number failed.
If you don't know for sure that your value can be converted to a number, you should ensure that tonumber succeded befor you do any operations on its return value.
local numberValue = tonumber(value)
if not numberValue then
print("converting value to a number failed)
return
end
-- at this point you know numberValue is a number
So if you wanted to write a function that ensures a string represents a number you could do something like this:
function IsNumber(value)
return tonumber(value) and true or false
end
I have created a function that (pseudo)randomly creates a table containing numbers. I then loop this function until at least correct result is found. As soon as I've confirmed that at least one such result exists, I stop the function and return the table.
When I create tables containing small values, there are no issues. However, once the random numbers grow to the range of hundreds, the function begins to return nil, even though the table is true the line before I return it.
local sort = table.sort
local random = math.random
local aMin, aMax = 8, 12
local bMin, bMax = 200, 2000
local function compare( a, b )
return a < b
end
local function getNumbers()
local valid = false
local numbers = {}
-- Generate a random length table, containing random number values.
for i = 1, random( aMin, aMax ) do
numbers[i] = random( bMin, bMax )
end
sort( numbers, compare )
-- See if a specific sequence of numbers exist in the table.
for i = 2, #numbers do
if numbers[i-1]+1 == numbers[i] or numbers[i-1] == numbers[i] then
-- Sequence found, so stop.
valid = true
break
end
end
for i = 1, #numbers-1 do
for j = i+1, #numbers do
if numbers[j] % numbers[i] == 0 and numbers[i] ~= 1 then
valid = true
break
end
end
end
if valid then
print( "Within function:", numbers )
return numbers
else
getNumbers()
end
end
local numbers = getNumbers()
print( "Outside function:", numbers )
This function, to my understanding, is supposed to loop infinitely until I find a valid sequence. The only way that the function can even end, according to my code, is if valid is true.
Sometimes, more often than not, with large numbers the function simply outputs a nil value to the outside of the function. What is going on here?
You're just doing getNumbers() to recurse instead of return getNumbers(). This means that if the recursion gets entered, the final returned value will be nil no matter what else happens.
In the else case of the if valid then, you are not returning anything. You only return anything in the valid case. In the else case, a recursive call may return something, but then you ignore that returned value. The print you see is corresponding to the return from the recursive call; it isn't making it out the original call.
You mean to return getNumbers().
For some reason it doesn't appear to work to pass in a table key as a function argument, what is the trick to do this?
I'm trying to wrap the for loop iteration technique in vanilla Lua into a function that has three arguments: (1) the table to iterate, (2) the table_key to check each time, and (3) the value to find. If a match is found, return it, otherwise return nil.
function table_find_match(table, table_key, match_value)
for i=1, #table do
local this = table[i]
if this[table_key] == match_value then
return this[table_key]
end
end
return nil
end
local table_example = {
{
key_example = "string_value_1"
},
{
key_example = "string_value_2"
}
}
local result = table_find_match(table_example, key_example, "string_value_1")
print(result)
Found a solution, if I pass in the table key as a string it works, such as
table_find_match(table_example, "key_example", "string_value_1")
but I really dislike having to convert it into a string, if anyone knows any other workaround to this please share
If you pass it like table_find_match(table_example, key_example, "string_value_1")
the key_example is now considered as a (nil) variable if not defined before executing, so it has to be like
local key_example = "key_example"
local result = table_find_match(table_example, key_example, "string_value_1")
print(result)
local meshId = message:sub(message, message:find(message, "/hat%s%d"), message:find(message, "/hat %d+"))
The message:find() returns two values; the first character and the last character. How would I make it only return the last character?
Simply, I think solution. just second prameter return
function returnTwo(...)
local a, b = message:find(...)
return b
end
wrap message:find function and return second value
How about?
If a function returns more than one parameter, you can use select(2, functioncall()) to get the second parameter. For example:
function returntwo() return "first", "second" end
print(select(2, returntwo())) -- prints "second"
In the case in question, you'd use it as local meshId = message:sub(message, select(2, message:find(message, "/hat%s%d")), select(2, message:find(message, "/hat %d+")))
I'd like to format a number to look like 1,234 or 1,234,432 or 123,456,789, you get the idea. I tried doing this as follows:
function reformatint(i)
local length = string.len(i)
for v = 1, math.floor(length/3) do
for k = 1, 3 do
newint = string.sub(mystring, -k*v)
end
newint = ','..newint
end
return newint
end
As you can see, a failed attempt, my problem is that I can't figure out what the error is because the program I am running this in refuses to report an error back to me.
Here's a function that takes negative numbers, and fractional parts into account:
function format_int(number)
local i, j, minus, int, fraction = tostring(number):find('([-]?)(%d+)([.]?%d*)')
-- reverse the int-string and append a comma to all blocks of 3 digits
int = int:reverse():gsub("(%d%d%d)", "%1,")
-- reverse the int-string back remove an optional comma and put the
-- optional minus and fractional part back
return minus .. int:reverse():gsub("^,", "") .. fraction
end
assert(format_int(1234) == '1,234')
assert(format_int(1234567) == '1,234,567')
assert(format_int(123456789) == '123,456,789')
assert(format_int(123456789.1234) == '123,456,789.1234')
assert(format_int(-123456789.) == '-123,456,789')
assert(format_int(-123456789.1234) == '-123,456,789.1234')
assert(format_int('-123456789.1234') == '-123,456,789.1234')
print('All tests passed!')
Well, let's take this from the top down. First of all, it's failing because you've got a reference error:
...
for k = 1, 3 do
newint = string.sub(mystring, -k*v) -- What is 'mystring'?
end
...
Most likely you want i to be there, not mystring.
Second, while replacing mystring with i will fix the errors, it still won't work correctly.
> =reformatint(100)
,100
> =reformatint(1)
,000
That's obviously not right. It seems like what you're trying to do is go through the string, and build up the new string with the commas added. But there are a couple of problems...
function reformatint(i)
local length = string.len(i)
for v = 1, math.floor(length/3) do
for k = 1, 3 do -- What is this inner loop for?
newint = string.sub(mystring, -k*v) -- This chops off the end of
-- your string only
end
newint = ','..newint -- This will make your result have a ',' at
-- the beginning, no matter what
end
return newint
end
With some rework, you can get a function that work.
function reformatint(integer)
for i = 1, math.floor((string.len(integer)-1) / 3) do
integer = string.sub(integer, 1, -3*i-i) ..
',' ..
string.sub(integer, -3*i-i+1)
end
return integer
end
The function above seems to work correctly. However, it's fairly convoluted... Might want to make it more readable.
As a side note, a quick google search finds a function that has already been made for this:
function comma_value(amount)
local formatted = amount
while true do
formatted, k = string.gsub(formatted, "^(-?%d+)(%d%d%d)", '%1,%2')
if (k==0) then
break
end
end
return formatted
end
You can do without loops:
function numWithCommas(n)
return tostring(math.floor(n)):reverse():gsub("(%d%d%d)","%1,")
:gsub(",(%-?)$","%1"):reverse()
end
assert(numWithCommas(100000) == "100,000")
assert(numWithCommas(100) == "100")
assert(numWithCommas(-100000) == "-100,000")
assert(numWithCommas(10000000) == "10,000,000")
assert(numWithCommas(10000000.00) == "10,000,000")
The second gsub is needed to avoid -,100 being generated.
I remember discussing about this in the LÖVE forums ... let me look for it...
Found it!
This will work with positive integers:
function reformatInt(i)
return tostring(i):reverse():gsub("%d%d%d", "%1,"):reverse():gsub("^,", "")
end
On the link above you may read details about implementation.